Rav Bertzi’s daughter, Gittel, once told how her father healed a young boy of thirteen who was born mute. The child was brought to the rebbe and Rav Bertzi asked that he be placed by his side during the time he recited the Birkas Hachodesh – the blessing of the new month. He turned to child who had never spoken a word in his life and said simply, “Repeat after me: Yehi.”
The child opened his mouth and for the first time in his life, miraculously uttered, “Yehi.”
“Ratzon,” continued Rav Bertzi, with the child repeating, “Ratzon...”
“Milfanecha,” continued the tzaddik, and the no longer mute child said, “Milfanecha.”
This went on word after word until the child was completely cured of his inability to speak. (Divrei Yimei Yissacher Ch. 10 p. 111)
